Two-stroke internal-combustion engine.



W. JEFFARES.

TWO-STROKE INTERNAL COMBUSTION ENGINE.

APPLICATION FILED IuLY 29.1915.

Batented Oct. 19, 1915.

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WILLIAM J'EFFARES, 0F MALIN, IRELAND.

TWO-STROKE INTERNAL-COMBUSTION ENGINE.

Application filed July 29, 1915.

To all whom it may concern:

Be it known that I, \VILLIAM J EFFARES, a subject of the King of Great Britain, residing at- Malin, county Donegal, Ireland, have invented certain new and useful Improvements in Two-Stroke Internal-Combustion Engines, of which the following is a specification.

This invention relates to two-stroke internal combustion engines of the kind in which the air or gas is compressed in the crank chamber and delivered to the cylinder through a transfer passage.

It is the object of this invention to provide a simple construction embodying improved control and delivery of the gases.

A further object of the invention is to provide simple means for mixing the fuel with the air preferably after some or the whole of the air has entered the cylinder.

The accompanying drawings show diagrammatically how the invention may be carried into effect.

In these, Figure l is a central vertical section of a single cylinder engine of the type in which the air is compressed in the crank chamber. Fig. 2 is a horizontal section on the line 2-2 of Fig. 1, and Fig. 3 is a vertical section approximately on the line 3-3 of Fig. 1, showing a modification.

Like letters indicate like parts throughout the drawings.

The underside of the piston Z operates, in the case illustrated, as an air pump, air entering by the inlet port A when the piston Z approaches the upper limit of its stroke, such air being compressed in the crank chamber B on the downstroke of the piston and then forced up the transfer passage C and delivered from there to the combustion chamber D as shown by the arrows in Figs. 1 and 2.

It will be noticed that the gas passes across the upper end of a chamber E in which works a piston valve F actuated by a rocker G and cam H. By means of the cam the piston normally remains in its highest position, in which the passage across the chamber E is obstructed, and communication between the transfer passage C and the cylinder is obstructed. Toward the end of the working stroke the piston uncovers the exhaust port K, and simultaneously, or shortly afterward, the piston valve Specification of Letters Patent.

Patentedflct. 19, 1915.

Serial No. 42,654.

F is allowed to drop under the influence of the spring J allowing air compressed in the crank chamber to enter the combustion chamber and fill the cylinder, forcing out the exhaust gas. Directly filling is eflected the cam H raises the piston valve F and the cylinder remains cut off from the crank chamber.

If desired gas may be supplied to the port A and crank chamber, but where air alone is compressed in the crank chamber this may be carbureted in any suitable manner. Preferably the fuel is added just as the air enters the combustion chamber and after a certain quantity has entered the cylinder so that a certain scavenging effect can be obtained through the admission of pure air while the exhaust port K is open.

The preferred arrangement for supplying fuel is shown in Fig. 3, which is a diagrammatic sectional view. The cylinder E containing the piston valve F communicates by a tube L with a fuel pump cylinder L. This contains the fuel pump piston N which, as it drops, forces fuel through the passage L and non-return valve L3 into the piston valve chamber E. As the pump piston N rises it draws in a charge of fuel through the inlet pipe M and non-return valve M The piston N is operated by any suitable cam or the like on the engine (not shown), and preferably delivers the fuel after a certain quantity of the air has entered the cylinder.

Preferably the end of the rocker G actuating the piston valve F is engaged by a lifter P whereby the rocker and piston valve can be held raised to any extent, which serves as a means of control for the quantity of air or gas supplied to the combustion chamber. When the piston valve has dropped there is a clear unobstructed passage for the air or gas from the crank chamber into the combustion chamber. In previous cases where the supply of transferred gas has been controlled by a piston valve the gas has been caused to pass through the valve. In the present case the valve is of very simple and cheap construction.

By the present invention a very simple construction results enabling much higher efliciency to be obtained from an engine of the crank case compression type than is customary. Also, by varying the drop of the piston valve the supply to the combustion chamber can be very easily controlled.

lVhat I claim as my invention, and desire to secure by Letters Patent is 1. In a two-stroke internal combustion engine, the combination of a power cylinder a power piston therein, a crank chamber in which air is compressed by the power piston, a transfer passage between said crank chamber and the upper end of said power cylinder, a piston valve cylinder interposed between said transfer passage and said upper end of the power cylinder, apiston valve which normally obstructs the communication between said transfer passage and the power cylinder but at the right time moves to permit the compressed air a clear passage across the piston valve cylinder, and a fuel pump which supplies fuel to the air as it passes through the piston valve cylinder, substantially as set forth.

2. In a two-stroke internal combustion engine, the combination of a power cylinder a said valve downward,'means operated by the engine for lifting said valve, and means for varying the distance through which said valve drops, substantially as set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

WVILLIAM JEFFARES.

Witnesses HUGH SWEENEY, TrIoMAs Ur. LOGUE.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. 0. 

